Used often in First Person Shooters when someone acheives a one-hit-kill.

Niko OneShot is the protagonist of the hit indie video game OneShot.

el gatto

A cool game

1. A meta puzzle adventure game in which you must guide the cat-like protagonist, Niko, using files from outside the game to solve the game's puzzles. This game was published by Future Cat LLC and developed by Nightmargin.

A oneshot is a short fanfic/fanfiction, often only one page long.

A game about someone named Niko getting trapped inside a world without a sun
You figure it out from there